During chromium electroplating of the inside diameter of gun barrels, the plater aims for a predetermined plate thickness and uniformity. The plater has a certain degree of experience, which tells him or her that if he or she runs the plating process for an hour with certain plating parameters on a given barrel, a certain chromium plate thickness will be achieved.
The prior art process is essentially blind, inasmuch as the thickness and evenness of the plate being formed is not available to the plater during the plating process. If the parameters which affect plating, such as surface passivation, concentration of solutes in the electrolyte, temperature, symmetrical placement of the anode in the bore, or flow rate of the electrolyte in the flowthrough plating process, combine to give any undesirable plating conditions, the plating process will continue with these undesirable conditions. Because of its blind nature, the plating process continues to follow the precalculated parameters, and the unacceptable condition is only found after a three hour plating run, for example, after the tube has been rinsed and dried. Perhaps, additional personnel or equipment will need to be called to evaluate the condition of the product.
Of course, up to now thick barrels were plated without measuring the thickness of the deposited chromium or other metal. No known process or method exists at this time to determine the plating thickness in real time.
The measuring methods for the plated thickness at the present time are done manually, such as by use of a star or an air gage. The method for correcting the problem, if the plate was not acceptable, was to strip the plated metal by a reverse plating method. Honing was also used. The tube was then replated via the same method described above.
Prior art methods for correcting the plating thickness such as in gun barrels have resulted in increased expenditure of manpower and resources. They cause delay and duplication of work, and slow down production schedules, thereby interrupting other parts of the production process.
Accordingly, it is an object of this invention to provide a method of determining the thickness of plating as it is being deposited on a surface.
Yet another object of this invention is to provide a real time measuring method which is capable of displaying the measurements being made, at various points in the tube.
Another object of the present invention is to provide a real time method for plating in which corrections and conditions can be redily implemented to keep production schedules and prevent duplication of work.
Other objects will appear hereinafter.